Walking and running can be defined as methods of locomotion involving the use of the two legs, alternately, to provide both support and propulsion, with at least one foot being in contact with the ground at all times. While the terms gait and walking are often used interchangeably, the word gait refers to the manner or style of walking, rather than the actual walking process. The gait cycle is the time interval between the exact same repetitive events of walking.
The defined cycle can start at any moment, but it typically begins when one foot contacts the ground and ends when that foot contacts the ground again. If it starts with the right foot contacting the ground, then the cycle ends when the right foot makes contact again. Thus, each cycle begins at initial contact with a stance phase and proceeds through a swing phase until the cycle ends with the limb's next initial contact. Stance phase accounts for approximately 60 percent, and swing phase for approximately 40 percent, of a single gait cycle.
Hard surfaces in modern human environments have changed the forces encountered by the human musculoskeletal system during the gait cycle as compared to the forces which it evolved to sustain. Impact energies from such surfaces enter the body through boney and dense tissues and through soft and fatty tissues. Such impact energy frequently causes physical damage leading to injury, in particular injury of the foot. At times, this type of physical injury can be treated by an orthotic insert.
Functional orthotic inserts may be placed in a shoe either on top of or in place of the insole to correct foot alignment and side-to-side movement during standing, walking, running to influence the orientation of the bones in a human foot and to influence the direction and force of motion of the foot or parts of the foot. Orthotics thereby decrease pain, not only in the foot, but also in other parts of the body such as the knee, hip and lower back. They can also increase stability in an unstable joint and prevent a deformed foot from developing additional problems. However, conventional devices are not dynamic as designed. Conventional orthotic devices typically include a shimmed, rigid post and as a result, dynamic adjustments to the foot during the gait cycle cannot be done. For example, adjustments such as making the foot tip out further, making the foot tip in further, raising the heel, raising the ball of the foot, and the like cannot be accomplished with conventional devices dynamically during the gait cycle.
Other causes of injury to the foot relate to underlying pathological disease states, such as by way of example, diabetes. Diabetes is a chronic disease that affects up to six percent of the population in the U.S. and is associated with progressive disease of the microvasculature. Complications from diabetes include not only heart disease, stroke, high blood pressure, diabetic retinopathy but also in particular diabetic neuropathic foot disease.
Diabetic neuropathic foot disease typically results in the formation of ulcers which commonly result from a break in the barrier between the dermis of the skin and the subcutaneous fat that cushions the foot during ambulation. This rupture may lead to increase pressure on the dermis. While there are devices and methods that purport to prevent plantar ulcer formation in a diabetic patient there are no orthotic devices on the market that treat the ulcer with dynamic offloading after formation.
Other types of injury to the foot include fractures, pressure sores, surgical sites and overuse injuries. Patho-mechanical foot dysfunctions include supination and pronation pathologies.
Therefore, what is needed are orthotic systems that can be used remedially to correct deformities resulting from physical and other injuries to the foot. What is also needed are dynamic orthotic systems that can be used therapeutically to address underlying pathologies and patho-mechanical foot dysfunctions to accurately and precisely position the foot throughout the gait cycle in order to promote proper function and alignment and mitigate excessive forces. In particular, what is needed is a dynamic orthotic suspension system that addresses foot pathologies that cause systemic pathologies such as ankle, knee and hip misalignment.